'97 Civic Shifting Roughness

I am taking a manual tranny course right now and can offer some of the book and ASE test answers, backed up by what I saw in lab.

Having to be real careful when letting up on the clutch pedal in order to get smoother shifting strongly suggests to me that your Civic needs a clutch job: New friction disc, pressure plate, release bearing. Also possibly resurfacing of the flywheel.

You can try checking the linkage bushings and pivot points shown at the link below, and performing the gearshift cable adjustments shown. Replace the bushings as needed, or apply light oil. I would not be optimistic this is going to help.

The engine mounts, if worn, can change the effective length of the clutch or gearshift cables and so cause problems.

Other causes are internal to the tranny, but these tend to be less likely than simply needing a clutch job.

For your reference: The Honda OEM MTF is also said by others to give smoother shifting.

100k miles is a good lifetime for a clutch, though this may vary a lot from one driver (and driving locale, etc.) to the other.

My 91 Civic has 180k miles on it, original clutch.

I had a Nissan whose clutch gave up at 115k miles.

"Me" wrote

... OTOH, the more I think about that MTF perhaps staying in there for 100k miles, the more likely I think it is that the tranny gears, for one, may have suffered some serious wear, or there is a lot of gunk still in there.

A second (or third and fourth?) MTF change may help. If you want to save money, you could flush it with ordinary SAE

10W-30 or 10W-40 motor oil. The owner's manual says this is okay for short periods (I think it gave a time period, at least; double check). Certainly for an effective flush, where I recommend you drive for a very short period between changes, it should be fine.

The most obvious symptom of needing a clutch job is slipping: While upshifting, the driver lets the clutch pedal out, whence the engine revs more than usual. This is because the clutch disc is not being held firmly between flywheel and pressure plate. Power is thus not being transferred properly to the wheels, so the expected acceleration of the car does not occur.

"Me" wrote

-------------------------------------------

Bleeding the brake fluid in the hydraulic system that moves the clutch might make it work closer to the 'design'. It should have been done the last time the brakes were bled, but nobody asks / nobody tells the mechanic.

'Curly'

A factor often overlooked is engine health. If the injectors are dirty or the ignition needs tune-up the clutch release can often be the first to suffer. Try a bottle of injector cleaner (most people favor Techron, but I have also had good results with the much cheaper Pyroil); can't hurt, might help. If the ignition tune-up parts (cap, rotor, wires and plugs) are old, replace them first. Except the plugs - which can be NGK - use only OEM parts for that. Many of us have learned the hard way about that.

Mike

Thanks for the suggestions. I think I'll try flushing it a few times with

10w30 and then add the Honda MTF. I may go ahead and flush the clutch (brake) fluid. I'm not sure if they did that when I bought the car or not. I know they did flush the brake fluid; not sure about the clutch. Guess it couldn't hurt and is a small amount anyway.

It doesn't slip at all so I'll hold my breath and save money on a new clutch until the problem gets worse. It's not really that bad now; just annoying.

Bob

"Me" wrote in news:JeadnXssPO2HYlbZnZ2dnUVZ snipped-for-privacy@comcast.com:

Clutch could be nearly worn out. When the linings are at the end of their lives, the "marcel" is greatly reduced, making it difficult to smoothly engage the clutch.

An experienced mechanic can tell how worn your clutch is by how much the slave cylinder rod sticks out.

"Michael Pardee" wrote

Michael, can you explain this? Do you mean the stuttering (or whatever irregular gas/air flow/spark at the cylinders) sort of fools the driver into thinking it's a shift problem? E.g. As the gas pedal is pressed during up shifting, engine RPM does not change the way it should, so the shifting is not all that smooth?

I would guess uneven acceleration which would in turn amplify a failing clutch symptom...

JT

Yes - the engine bogs down easily and becomes ragged. I think it may go into a subtle "pilot induced oscillation" where the engine starts to rev and the driver's foot lets out a bit more, only to put more load on the engine than it can handle. I could be wrong about that. I've noticed it in my older Volvo (1970) when the points needed attention and in an '84 300ZX when I ran it on cheap gas too long. My son's '94 Acura also started doing that, and a bottle of Techron improved it about 60-70 percent over the course of a week.

The first time I encountered it in the Volvo I assumed it was the clutch - until the morning the engine wouldn't start. After filing the points the clutch was magically smooth again, and the light came on over my head. "Sayyy...." After that, whenever the clutch got touchy I would rework the points and be stylin' again. OTOH, I had a work truck that wouldn't start one morning (you'd think it wouldn't need a tune-up after 150K miles/9 years!) and it never got "grabby." Huh.

Anyway, in the spirit of "make everything right first, then troubleshoot" I like to rule out tune-up issues.

Mike

"Michael Pardee" wrote

for brevity snipped the usual good anecdotes; please look back

I buy it. I also googled and this came up on at least one least web site, too. See

JT, I concur.

It's a very good point, IMO. Plus, one is not throwing money away by doing a tuneup, either.

I agree this is a proper troubleshooting approach.

Curly, That did the trick. Much better now. Thanks! Bob

-----------------------------------

See, I can guess them even when it's not Psychic Wednesday !!!

I'm glad for you. A crappy clutch would be hard to live with.

'Curly'